Paperclip icon is now the primary logo

The abstract four-square brand mark is replaced everywhere by the paperclip in app/icon.png (which is also the favicon), so there's one logo source.

Added

• components/Logo.tsx — <Logo size> renders app/icon.png via a static import (next/image); updating that one file updates the logo app-wide.

Changed

• components/TopBar.tsx — the file-menu pill mark now uses <Logo size={24} /> (dropped the inline SVG + accent-bg tile).
• components/CanvasEmptyState.tsx — the onboarding mark now uses <Logo size={40} /> next to the "ClipSpaces" wordmark.